As optics-based control systems become increasingly more commonplace, efforts to improve upon optical synthesizers continue to grow. Optical synthesizers generate and output an optical signal having a frequency that is adjusted to a desired frequency. More particularly, the optical signal is derived from an optical source, typically a single-frequency laser or multiple lasers, and a frequency reference which are then processed to output the desired frequency. While various advancements have been made to provide for more accurate and reliable optical synthesizers capable of producing a broader range of output frequencies, there is still much room for improvement in terms of at least efficiency and implementation.
One limitation of conventional optical synthesizers is their reliance on non-integrated systems. Currently available solutions, for instance, rely on input from various external references, such as microwave references, additional optical sources or lasers, modulators, as well as added control circuitry therefor, in order to establish absolute output frequencies. This not only adds to the cost of implementation, but the lack of simplicity prevents for more integrated or on-chip implementations. Furthermore, conventional optical synthesizers rely on light from an external laser source that is frequency-shifted from the comb frequency nearest the desired frequency. Such techniques not only consume much more power than necessary, but can also introduce ambiguities and inaccuracies to the resulting output. These techniques also practically limit the range of output frequencies to the tuning range of the external laser source.
Accordingly, there is a need for improved optical synthesis techniques, which not only provide for integrated or on-chip solutions and produce output over a wider range of output frequencies, but also consume substantially less power without adversely affecting accuracy and reliability.